As part of its trade war with the US, China has threatened to restrict exports of rare earths. These obscure minerals, on which the military and tech industries depend, are overwhelmingly produced in China. Katie Martin discusses how the world came to be so dependent on one country for such an essential part of the industrial supply chain with Lucy Hornby and Henry Sanderson.
Contributors: Josh Noble, weekend news editor, Katie Martin, capital markets editor, Henry Sanderson, commodities correspondent, and Lucy Hornby, deputy Beijing bureau chief. Producer: Fiona Symon